The prior art does not show the use of collagenated fabric wherein collagen fibers are chemically attached to fabric materials. Although it is well known that collagen developed from bovine tissue is not rejected from the human body and indeed, is used in plastic surgery extensively for filling in local bone or tissue defects by injection of collagen, making a more natural skin appearance, and is often used in removing facial lines, particularly "crow's feet" around the eyes, the use of these fibers had not been proposed for making area coverings, such as vascular grafts or heart valve prostheses. The state of the art prior to the invention is generally described in two publications by A. L. Rubin, et al.: "The Structure and Use of Collagen" in Biomaterials, pp. 157-184 (1969) and "Collagen Materials In Dialysis and Implantation", Transactions of the American Society of Artificial Organs, 14; 169-174 (1968).
In addition, a collagen impregnated vascular graft is described in U.S. Pat. No. 4,319,363. The vascular graft or implant of this prior art patent is obtained by implanting a rod or tube in a live host animal, such as sheep. Thereafter, collageneous tissue is allowed to grow on the implant to form a coherent tubular wall. The rod, covered by tissue, is then removed from the host animal, the collagenous tissue is removed from the rod and is tanned in glutaraldehyde to serve as the vascular graft.